The airfield was opened on 20 September 1941 as the
Army Air Force Basic Flying School, one of the fields used by the 30,000 Pilot Training Program. It provided basic air training for beginning pilots and crewmen. Many pilots and crews were trained here during the war, including
Women's Air Service Pilots (WASPs).
Auxiliary air fields used by
Merced Army Air Field (as the site was known at the time) during the war were: •
Merced Municipal Airport Auxiliary Field No. 1 •
Ballico Auxiliary Field No. 2 •
Howard Auxiliary Field No. 3 •
Athlone Auxiliary Field No. 4 •
Potter Auxiliary Field No. 5 •
Merced New Municipal Airport Auxiliary Field No. 6 •
Mariposa Auxiliary Field Postwar years With the end of the war
444th Bombardment Group (Very Heavy) arrived on 15 November 1945 from West Field,
Tinian with four squadrons (344th, 676th, 677th, and 678th) of wartime B-29s. The 444th operated from Merced for about six months with the 678th BS being re-designated as the 10th Recon Squadron and its aircraft being converted to the RB-29 configuration. The three
B-29 squadrons inactivated at Atwater on 6 May 1946 with the 10th Reconnaissance Squadron relocating to
Davis-Monthan Field,
Arizona where it turned in its RB-29 aircraft. The 444th was inactivated on 16 November 1947. During the summer of 1945, when most other air fields were winding down, Merced was expanded to accommodate the large air tankers then programmed to come into service. After the war ended, Merced was home to several air tanker squadrons and remained a training center for pilots and air crews.
93d Bombardment Wing for Castle AFB, after their record-setting round-the-world flight in 1957. Merced Army Air Field became
Castle Field on 17 January 1946, named for
Brigadier General Frederick Castle. On Christmas Eve 1944, Castle remained at the controls of his burning
B-17 Flying Fortress over
Europe while his crew bailed out, then was killed when the aircraft exploded; he was posthumously awarded the
Medal of Honor. The
93d Bombardment Group (Very Heavy) was activated at Merced on 21 June 1946, starting a nearly 50-year relationship with the airfield. The 93rd was a former
Eighth Air Force B-24 Liberator group which was assigned to Merced for
Boeing B-29 Superfortress training. The 93rd was one of SAC's first ten bomb groups. There were three initial operational squadrons (328th, 329th, and 330th) which absorbed the equipment and aircraft of the inactivated 444th BG. On 1 October 1946, the base was put on "minimal operations on caretaker status," with control of the facility under the Colorado Springs AAF. The 93rd Bomb Group, however remained active. It, along with the
509th Composite Group at
Roswell Army Air Field,
New Mexico, was all there was of
Strategic Air Command at that time. The base remained in this status until 1 May 1947 when it was reactivated. On 1 May 1947, Castle Field was reactivated under
Strategic Air Command. On 28 July 1947, the
93rd Bombardment Wing, (Very Heavy) was established and took over responsibility from the group. During 1947–1948, it flew
Boeing B-29 Superfortresses, but soon received the upgraded version of the B-29, the
Boeing B-50 Superfortress. In 1948, the entire wing deployed to
Kadena AB,
Okinawa, becoming the first
Strategic Air Command bomb group to deploy in full strength to the Far East. Castle Field was renamed Castle Air Force Base on 13 January 1948, this following the establishment of the USAF as a separate military service in September 1947. On 27 June 1949, the
Air Force Reserve's 447th Bombardment Group was activated at Castle and equipped with the B-29s formerly of the 93d Bomb Wing. The 447th remained active until 16 June 1951 when the group was activated and the aircraft and personnel sent to
Far East Air Forces as replacements for combat losses during the
Korean War. With the unit's departure, the 447th was inactivated. The
Convair B-36 Peacemaker entered SAC's inventory in 1948. The huge plane dwarfed earlier bombers and the 93rd, along with all other B-29 and B-50 bomb groups, was redesignated as "Medium." Only the B-36 groups were "Heavy." The wing began aerial refueling operations in October 1950, providing aerial refueling and navigational assistance for the July 1952 movement of the
31st Fighter-Escort Wing from the United States to Japan, the first jet fighter crossing of the Pacific Ocean, during the
Korean War. From 1953 to 1955, the wing flew
Boeing KC-97 Stratofreighters. All-jet
Boeing KC-135 tankers came on line in 1957. The 93d Bombardment Wing (Medium) received its first
Boeing B-47s in May 1954, but its involvement with the new Stratojet was curtailed on 29 June 1955 when the wing received the first production line
Boeing B-52B Stratofortress, making it the first SAC bomb wing to receive the new aircraft. The wing became SAC's primary B-52 aircrew training organization, incorporating KC-135 aircrew training for the air refueling mission in mid-1956. For this purpose, it set up the 4017th Combat Crew Training Squadron which was supposed to handle all B-52 crew training for the next few years. When the mission of B-52 training became too great a task for just one squadron, the Wing's other three squadrons took over the flight training role and the 4017th assumed responsibility for ground instruction in 1956. The 93d was SAC's primary B-52 training organization and retained some of its B-47s until 1956 for crew training purposes. It was one of the few wings in SAC to concurrently operate both the B-47 and B-52. In November 1956, the wing made non-stop B-52 flights of some around North America and to the North Pole. Although most of the wing's components were used for B-52 and KC-135 aircrew training between 1956 and 1995, one or more of its units sometimes participated in tactical operations, including tactical bombardment and aerial refueling. From April 1968 to April 1974, the 93rd operated a special B-52 replacement training unit to support SAC's B-52 operation in Southeast Asia. Also, the 328th and 329th Bomb Squadrons deployed to
U-Tapao Royal Thai Navy Airfield, Thailand where they flew combat missions over Vietnam, Cambodia, and Laos during the
Vietnam War. The wing won the SAC Bombing and Navigation Competition and the Fairchild Trophy in 1949, 1952, and 1970, and the Omaha Trophy as the outstanding SAC wing in 1970. In August 1990, the wing operated an aerial port of embarkation (APOE) for personnel and equipment deploying to Southwest Asia during
Desert Shield. In addition to aerial refueling, Castle-based KC-135 tankers ferried personnel and equipment, while B-52s deployed to strategic locations worldwide, including Saudi Arabia. B-52s bombed the Iraqi Republican Guard and targeted Iraqi chemical weapons, nuclear, and industrial plants during
Desert Storm, January–February 1991. On 1 September 1991, the 93rd Bombardment lost its operational KC-135 unit, the 924th Air Refueling Squadron, and its KC-135 aircrew formal training unit, the 329th Combat Crew Training Squadron. It also implemented the objective wing organization and was redesignated as the 93rd Wing (93 WG). On 1 June 1992, pursuant to the inactivation of Strategic Air Command and the establishment of the new
Air Combat Command (ACC), the 93rd Wing was transferred from SAC, reassigned to ACC, and renamed the 93rd Bomb Wing (93 BW). Shortly afterwards, nationwide base closures under the
BRAC process targeted numerous USAF installations, especially former SAC installations, to include Castle AFB. With BRAC closure of Castle AFB confirmed, the 322d Bomb Squadron was inactivated on 3 May 1994 and the wing was placed on non-operational status. However, the 93rd Bomb Wing continued to supervise the closure of Castle AFB. The 93rd Bomb Wing was inactivated on 30 September 1995 with the closure of Castle AFB, but was subsequently redesignated as the 93d Air Control Wing (93 ACW) and reactivated at
Robins AFB, Georgia on 29 January 1996.
Notable operations •
Operation Power Flite: First jet aircraft nonstop flight around the world (January 1957). • Nonstop, unrefueled KC-135 flight from
Yokota AB, Japan, to
Washington, D.C. (April 1958).
Closure The end of the
Cold War brought many changes to the Air Force, and Castle AFB was selected for closure under the
Defense Base Closure and Realignment Act of 1991 during Round II Base Closure Commission deliberations (BRAC 91). On 1 June 1992 the 93d was relieved from assignment to SAC and was reassigned to the newly formed
Air Combat Command (ACC). It was then redesignated as the 93d Bomb Wing, its B-52G aircraft given the ACC tail code of "CA" and the marking of blue tail stripes. The 322d Bomb Squadron was inactivated 3 May 1994 and the wing was placed on non-operational status. However, the 93d continued to supervise the closure of Castle AFB. The 93d Bomb Wing was inactivated on 30 September 1995 with the closure of Castle AFB. The
Castle Air Museum remains at the site. ==Civilian use==